Feeding ecology and reproductive dynamics of Carassius carassius (Linnaeus, 1758) in Dal Lake, Kashmir

Abstract

The Crucian carp (Carassius carassius), an invasive cyprinid in Dal Lake, Kashmir, plays a key ecological and commercial role in the region. However, its feeding and reproductive biology remain understudied in the temperate Himalayan ecosystem. This study examined seasonal variations in feeding activity and reproductive traits from December 2020 to May 2021, assessing feeding intensity, gastro-somatic index (GaSI), relative gut length (RGL), fecundity, and gonadosomatic index (GSI). Feeding intensity peaked in May (50% full stomachs) and was lowest in March (30%), with larger fish (181-220 mm) consuming more than smaller fish (100-140 mm). The mean RGL (1.79) confirmed omnivory, whereas GaSI peaked in May (1.43), indicating post-spawning compensatory feeding. Fecundity ranged from 7,265 to 44,363 eggs and was strongly correlated with body weight (R² = 0.931). The GSI values revealed a March spawning peak, with females investing more energy in reproduction than males. These findings highlight the species' adaptive feeding and reproductive strategies, offering insights into managing its invasive spread in the fragile ecosystem of Dal Lake.